Printed wiring boards (PWB), also referred to as printed circuit boards (PCB), are extensively used as a platform for mounting a variety of electrical components in electronic devices. These electrical components include passive devices like resistors, capacitors, inductors, switches, diodes, filters, and other radio-frequency (RF) components. Typically, passive devices represent a significant portion of the total number of electrical components present in a PWB circuit.
In addition to the electrical components, tunable components with movable parts, such as switches, can also be provided in the PWBs. Smaller and complex electronic devices require smaller switches. Current small solid-state switches are not ideal because they exhibit a finite leakage that prevents a complete switch-off. Further, available mechanical and electro-mechanical switches are bulky and consume a large amount of power. Micro electro-mechanical systems (MEMS) address these drawbacks. However, these MEMS devices are fabricated from crystalline silicon or silicon dioxide, which require fabrication methods that are not compatible with PWB fabrication. Therefore, MEMS devices made by this technology must be made separately, and then incorporated into PWBs.
There are a number of methods for embedding the electrical components and MEMS devices in the PWBs. One of these methods involves forming an interconnect section and a variable passive section on a substrate. The variable passive section may be formed from metal interconnect layers separated by a dielectric. The variable section comprises at least a movable element.
However, in existing methods, antennas are treated as a separate assembly and connected to RF front-ends. Individual silicon MEMS devices are used for tuning antennas and RF front-ends. These silicon MEMS devices are not compatible with the PWB fabrication process. Further, existing methods may not facilitate embedding a combination of MEMS devices and antennas on an organic substrate.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.